Conventionally, there has been known an electrical junction box in which a circuit structure is formed by electrically connecting two different circuit boards to each other and is housed in a housing (refer to Patent Document 1).    [Patent Document 1] Japanese Patent Laid-Open No. 10-35375
To decrease the size of the circuit structure configured as described above, it is conceivable that each of circuits corresponding to the circuits formed on the two circuit boards is formed on the top and back surfaces of an insulating plate. Thereby, each of the circuits corresponding to the two circuit boards is formed on the top and back surfaces of one insulating plate, so that the circuit structure can be made small in size.
However, according to the above-described configuration, since the insulating plate is interposed between both of the circuits, when an electronic part to be connected to both of the circuits is mounted on the circuit structure, it is necessary that, for example, one end of a jumper wire be connected to one terminal of the electronic part connected to a conducting path on one surface of the insulating plate, and the other end of the jumper wire be extended to the other surface of the insulating plate and be connected to a conducting path on the other surface of the insulating plate. Therefore, in the case where a large number of electronic parts are mounted, the process for connecting the jumper wire to the conducting path is troublesome.